Firesets are commonly used in military, construction, and industrial applications to detonate explosives. A conventional fireset includes a low energy exploding foil initiator (LEEFI) and a drive circuit. The LEEFI generally has a bridge wire with low electrical resistance (e.g., about 0.025-Ohms) placed in close proximity to a foil. The foil may be made of Mylar or some other suitable material. The foil is placed in close proximity (i.e., in contact or nearly so) with an explosive material. Various explosive materials are known in the art, and include, for example, C-4, Semtex, TNT, and nitroglycerin.
To detonate the explosive material, the drive circuit is activated to pass a high current through the LEEFI. The high current causes the bridge wire within the LEEFI to vaporize. The vaporized bridge wire forms a rapidly expanding plasma, which accelerates a metal foil “flyer” away from the bridge wire at high speeds. The flyer's path is designed to impact an initiator explosive, wherein the kinetic “slap” from the flyer delivers enough energy to initiate a detonation.
Various fireset designs have been proposed. For example, U.S. Pat. No. 5,600,293 to Donald Hunter discloses a fireset with a magnetically actuated triggering mechanism. Also, U.S. Pat. Nos. 6,138,571 and 6,634,298 to Jim Denney disclose firesets having drive circuits that each include a high voltage capacitor and a metal-oxide-semiconductor field-effect transistor (MOSFET) switch. When activated, the MOSFET switch causes charge on the capacitor to suddenly be dumped through the LEEFI, triggering detonation.